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本文次要钻研一下 dubbo-go 的 gracefulShutdownFilter
gracefulShutdownFilter
dubbo-go-v1.4.2/filter/filter_impl/graceful_shutdown_filter.go
type gracefulShutdownFilter struct {
activeCount int32
shutdownConfig *config.ShutdownConfig
}
- gracefulShutdownFilter 定义了 activeCount、shutdownConfig 属性
init
dubbo-go-v1.4.2/filter/filter_impl/graceful_shutdown_filter.go
func init() {
var consumerFiler = &gracefulShutdownFilter{shutdownConfig: config.GetConsumerConfig().ShutdownConfig,
}
var providerFilter = &gracefulShutdownFilter{shutdownConfig: config.GetProviderConfig().ShutdownConfig,
}
extension.SetFilter(constant.CONSUMER_SHUTDOWN_FILTER, func() filter.Filter {return consumerFiler})
extension.SetFilter(constant.PROVIDER_SHUTDOWN_FILTER, func() filter.Filter {return providerFilter})
}
- init 办法别离创立并设置了 CONSUMER_SHUTDOWN_FILTER、PROVIDER_SHUTDOWN_FILTER
Invoke
dubbo-go-v1.4.2/filter/filter_impl/graceful_shutdown_filter.go
func (gf *gracefulShutdownFilter) Invoke(ctx context.Context, invoker protocol.Invoker, invocation protocol.Invocation) protocol.Result {if gf.rejectNewRequest() {logger.Info("The application is closing, new request will be rejected.")
return gf.getRejectHandler().RejectedExecution(invoker.GetUrl(), invocation)
}
atomic.AddInt32(&gf.activeCount, 1)
return invoker.Invoke(ctx, invocation)
}
- Invoke 办法先判断 gracefulShutdownFilter 的 rejectNewRequest 是否为 true,若为 true 则执行 getRejectHandler().RejectedExecution,否则执行 atomic.AddInt32 及 invoker.Invoke(ctx, invocation)
OnResponse
dubbo-go-v1.4.2/filter/filter_impl/graceful_shutdown_filter.go
func (gf *gracefulShutdownFilter) OnResponse(ctx context.Context, result protocol.Result, invoker protocol.Invoker, invocation protocol.Invocation) protocol.Result {atomic.AddInt32(&gf.activeCount, -1)
// although this isn't thread safe, it won't be a problem if the gf.rejectNewRequest() is true.
if gf.shutdownConfig != nil && gf.activeCount <= 0 {gf.shutdownConfig.RequestsFinished = true}
return result
}
- OnResponse 办法先执行 atomic.AddInt32(&gf.activeCount, -1),之后判断 gf.activeCount 是否小于等于 0,是的话则标记 gf.shutdownConfig.RequestsFinished 为 true
rejectNewRequest
dubbo-go-v1.4.2/filter/filter_impl/graceful_shutdown_filter.go
func (gf *gracefulShutdownFilter) rejectNewRequest() bool {
if gf.shutdownConfig == nil {return false}
return gf.shutdownConfig.RejectRequest
}
- rejectNewRequest 办法在 shutdownConfig 为 nil 是返回 false,否则返回 gf.shutdownConfig.RejectRequest 的值
getRejectHandler
dubbo-go-v1.4.2/filter/filter_impl/graceful_shutdown_filter.go
func (gf *gracefulShutdownFilter) getRejectHandler() filter.RejectedExecutionHandler {
handler := constant.DEFAULT_KEY
if gf.shutdownConfig != nil && len(gf.shutdownConfig.RejectRequestHandler) > 0 {handler = gf.shutdownConfig.RejectRequestHandler}
return extension.GetRejectedExecutionHandler(handler)
}
- getRejectHandler 办法在 gf.shutdownConfig 不为 nil 且 gf.shutdownConfig.RejectRequestHandler 长度大于 0 时设置 handler 值为 gf.shutdownConfig.RejectRequestHandler,之后依据该值执行 extension.GetRejectedExecutionHandler
小结
gracefulShutdownFilter 定义了 activeCount、shutdownConfig 属性;其 Invoke 办法先判断 gracefulShutdownFilter 的 rejectNewRequest 是否为 true,若为 true 则执行 getRejectHandler().RejectedExecution,否则执行 atomic.AddInt32 及 invoker.Invoke(ctx, invocation);其 OnResponse 办法先执行 atomic.AddInt32(&gf.activeCount, -1),之后判断 gf.activeCount 是否小于等于 0,是的话则标记 gf.shutdownConfig.RequestsFinished 为 true
doc
- graceful_shutdown_filter